Continuous mixing apparatus for flowable products

Abstract

To continuously mix two flowable products such as a solid product in the divided state and a liquid product, two concentric ducts are provided each with associated entraining means. The entraining means of the outer duct serves to move a first one of the flowable products along the duct from an entry port towards an exit port for the mixed products and includes a helical element urging the first product into rotation in passage along the outer duct. The second duct opens into the outer duct between the entry and exit ports of that duct and the entraining means of the inner duct serves to move the second flowable product through the inner duct and into the outer duct in the center of the first product stream.

I claim: 
     
       1. Apparatus for continuously mixing two flowable products, the apparatus comprising a first duct having an entry port through which a first flowable product stream can pass into the first duct and an exit port through which the mixed flowable products can pass out of the first duct, first entraining means provided with a helical element and serving to impart helical motion to the first flowable product stream within the first duct, a second duct concentrically mounted within the first duct and provided with an entry port through which a second flowable product stream can pass into the second duct, the second duct being arranged to open into the first duct between the said entry and exit ports thereof to allow said second stream to pass into the first duct, and second entraining means serving to move said second flowable product stream along the second duct, the first and second entraining means being distinct from each other and serving to move the product streams in the same direction. 
     
     
       2. Apparatus according to claim 1, in which the second entraining means comprises a helical element installed within the second duct. 
     
     
       3. Apparatus according to claim 2, in which the helical elements of the first and second entraining means are of opposite hands and are arranged to be rotated in opposite senses by drive means of said entraining means. 
     
     
       4. Apparatus according to claim 2, in which the helical elements of the first and second entraining means are of the same hand, and are arranged to be rotated in the same sense by common drive means of the entraining means. 
     
     
       5. Apparatus according to claim 2, in which the first entraining means includes injection means arranged to inject said first flowable product in the form of a liquid into the first duct, the apparatus further comprising means arranged to supply said second flowable product in the form of a solid in a divided state into the second duct. 
     
     
       6. Apparatus according to claim 5, in which said liquid injection means in arranged to inject liquid tangentially into the first duct. 
     
     
       7. Apparatus according to claim 6, in which the helical element of the first entraining means is formed by a stationary helical element provided within the first duct, the second entraining means comprising its said helical element and drive means for rotating that element. 
     
     
       8. Apparatus according to claim 7, in which the stationary helical element is formed by a helical strip projecting inside the first duct. 
     
     
       9. Apparatus according to claim 7, in which the stationary helical element is formed by a helical groove provided internally around wall means defining the boundary of the said duct. 
     
     
       10. Apparatus according to claim 5, in which the helical element of the first entraining means is formed by a propeller disposed within the first duct adjacent the second duct and fast with the helical element of the second entraining means whereby this latter element is caused to rotate as a consequence of the action upon the propeller of the liquid injected into the first duct by said injection means. 
     
     
       11. Apparatus according to any one of claims 2, 3, 4, 5, 6 or 7, in which the helical element installed within the second duct extends out of the second duct into the first duct. 
     
     
       12. Apparatus according to claim 1, in which the first duct is further provided with a second entry port downstream of where the second duct opens into the first duct. 
     
     
       13. Apparatus according to claim 1, in which the first duct is supplied with flowable products via a plurality of pipes each opening into the duct upstream of the opening of the second duct into the first duct, the said pipes being provided with metering devices. 
     
     
       14. Apparatus according to claim 1 or claim 5, in which the second duct is supplied with flowable products via a plurality of pipes distributed over its length and each provided with a metering device. 
     
     
       15. Apparatus according to claim 1, in which a plurality of second ducts are provided leading into the first duct. 
     
     
       16. Apparatus according to claim 1, in which the second entraining means comprises means arranged to supply a pulsed stream of gas to the second duct. 
     
     
       17. Apparatus according to claim 16, in which a deflector element is provided where the second duct opens into the first duct. 
     
     
       18. Apparatus according to claim 1 and arranged to mix a flowable solid product supplied to its second duct with another flowable product, the apparatus including spheroids of a greater headness than the solid product, and means arranged to feed the spheroids into the second duct together with the solid product. 
     
     
       19. Apparatus according to claim 18, in which a grid is provided in the path of mixture leaving the exit port of the first duct, said grid serving to recover the spheroids to enable their recycling back to the second duct. 
     
     
       20. Apparatus for continuously mixing liquid products with solid products in the divided state, the apparatus comprising at least two concentric ducts the outermost one of which is provided with an entry port through which a first product stream can pass into the duct and an exit port through which mixed products can pass out of the duct, the outermost duct being further provided with helical entraining means for urging into rotation the first product stream in passage along the duct, the or each inner duct being of smaller cross-section than the outermost duct and being provided with entraining means for moving a second product stream therealong, the or each inner duct extending into the outermost duct and opening therewithin downstream of its entry port and upstream of its exit port, the said entraining means being distinct from each other and acting on the products in the same direction.